Belts transfer forces and need to be able to satisfy increasingly tough demands. The requirement for greater power in less space means that ever larger forces are transferred at ever higher ambient temperatures. The production and structure of V-belting, flat belts, toothed belts and conveyor belts are becoming increasingly complex. The performance of these belts is determined by the quality of the different rubber compounds, the additional reinforcing supports and the bond between them. .... Show more Show less

Rhein Chemie offers innovative solutions for the production of belts, covering everything from compound processing and pre-treatment of components to fabrication and, last but not least, vulcanization. Using processing promoters from the Aktiplast®range for compound processing can shorten mixing times, improve filler dispersion and the dynamic behavior of the vulcanizate, and facilitate mold removal. For example, Aktiplast® PP is particularly suited to sticky compounds made from hydrogenated nitrile rubber and ethylene-vinylacetate rubber (HNBR and EVM, e.g. Levapren®). Products from the Aflux®range enhance the compound’s flow properties, i.e. they improve fabric penetration and fiber coverage. Depending on the specific compound, Aflux® 42 is suitable for chloroprene and ethylene-propylene-diene rubber (CR, EPDM), Aflux® 54 or Aflux® 37 for hydrogenated nitrile rubber (HNBR) and Aflux® 18 for ethylene-vinylacetate rubber (EVM). They also reduce stickiness. The millable polyurethane rubber Urepan® 643 G is ideal for belts requiring good oil resistance, mechanical strength and high abrasion resistance. Temporary storage of the rubber sheets produced during/after the mixing process is easy thanks to release agents from the Rhenodiv® range. The powder release agent Rhenodiv® BO-505-2 is ideal for compounds used to make conveyor belts, while Rhenodiv® 4100 was specially developed for conveyor belt vulcanization, replacing conventional aids such as silicone paper or semi-permanent mold release agents. The vulcanized fibers and fabrics typically used as reinforcing supports for drive elements can be pretreated using an RFL dip. The precondensed resorcinol formaldehyde resin Rhenosin® T serves as a bonding agent, and bonding with the fiber can be further enhanced by adding Rhenocure® TT. The cross-linking system is crucial to the quality of rubber products such as belts that are subject to high dynamic stresses. Polymer-bound chemicals (Rhenogran®) can be dispersed quickly and homogeneously. The peroxide vulcanization of ethylene vinyl acetate rubber (EVM) can be activated using Rhenogran® TAC-50. Rhein Chemie offers ETU-free cross-linking systems for compounds based on chloroprene rubber (CR). Rhenogran® HPCA-50 (activator), combined with Rhenogran® MTT-80, is a tailor-made vulcanization accelerator for producing vulcanizates with improved resistance to hardening. Rhenogran® MBI-80 works in synergy with other antioxidants to protect peroxide-cross-linked ethylene-propylene-diene rubber (EPDM) compounds against aging without causing discoloration. Two examples of specialty additives are Rhenofit® OCD, an antioxidant specifically for chloroprene rubber (CR) compounds, and the plasticizer Rhenosin® VU-90, which improves the low-temperature flexibility of chloroprene rubber vulcanizates. Key reinforcing supports in belts include long fibers and fabrics based on polyester, aramid, nylon, rayon and glass, and short fibers up to 1.0 mm long. For good dynamic properties and the transfer of high forces, it is extremely important to have a good bond between rubber matrix and fiber, combined with perfect fiber dispersion. Rhein Chemie supplies predis- persed aramid short-fiber pulp (Rhenogran® P91 series and Rhenogran® AFP series) with various polymer binders.